JP3076033B1 - Optical information recording / reproducing apparatus and information recording medium - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: In a writable optical disc, the start and end of a mark are slightly different depending on the structure of the disc, the composition of a recording film, and the like, so that it is necessary to adjust the position of a write pulse. SOLUTION: An optimum position of a mark start end portion and a mark end portion is obtained by actually writing it on a test disk.
The obtained optimal position information is recorded in advance on all disks. The recording device reads the recorded optimal position information, and records the mark start end and the mark end at the optimal positions based on the read information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recording and reproducing optical information on a recordable information recording medium and a configuration of the information recording medium.

[0002]

2. Description of the Related Art An apparatus for recording and reproducing optical information, particularly digital information, on an information recording medium has attracted attention as means for recording and reproducing a large amount of data.

[0003] One of recordable optical information recording media is a phase-change optical disk. Recording on a phase-change optical disk is performed by irradiating a rotating disk with a light beam of a semiconductor laser and heating and melting the recording film. The ultimate temperature of the recording film and the cooling process differ depending on the intensity of the light beam, and a phase change of the recording film occurs.

When the light beam intensity is high, the recording film is rapidly cooled from a high temperature state, so that the recording film becomes amorphous. When the light beam intensity is relatively weak, the recording film is gradually cooled from a medium high temperature state, so that the recording film is crystallized. I do. The amorphous part is called a normal mark, and the crystallized part between the marks is usually called a space. Then, binary information is recorded in the mark and the space. Normally, the laser power when the light beam intensity is high is called peak power, and the laser power when the light beam intensity is low is called bias power.

At the time of reproduction, a light beam weak enough to cause no phase change in the recording film is irradiated, and the reflected light is detected. Normally, a mark portion that has been made amorphous has a low reflectance, and a space portion that has been crystallized has a high reflectance. Therefore, a difference in the amount of reflected light between the mark portion and the space portion is detected to obtain a reproduction signal.

[0006] As a method of recording data on a phase change type optical disc, a mark position recording method (or PPM method) for recording information at a position of a mark of a fixed length and a mark for recording information in a mark length and a space length. There is an edge recording method (or PWM method), and usually, the mark edge recording method has a higher information recording density.

In the mark edge recording method, a longer mark is recorded than in the mark position recording method. When a long mark is recorded by irradiating peak power to a phase change optical disc, the width in the radial direction becomes larger toward the rear half of the mark due to heat accumulation in the recording film. This greatly impairs the signal quality, such as loss of linearity of the recorded signal, increase in jitter at the time of reproduction, occurrence of unerased parts at the time of direct overwriting, and occurrence of signal crosstalk between tracks at the time of reproduction.

In order to increase the recording density, it is conceivable to shorten the length of the mark and the space to be recorded. In this case, particularly when the space length is shortened, the heat at the end of the recorded mark reduces the space. Conduction causes heat interference to affect the temperature rise at the beginning of the next mark, or conversely, heat at the beginning of the next recorded mark affects the cooling process at the end of the previous mark. When thermal interference occurs in the conventional recording method, the edge position of the mark fluctuates, and there is a problem that the error rate at the time of reproduction increases.

In order to solve the above problems, Japanese Patent Laid-Open No.
In Japanese Patent No. 9959 (corresponding to U.S. Pat. Nos. 5,490,126 and 5,636,194), a signal corresponding to a mark of mark edge recording is decomposed into a starting portion having a fixed width, a pulse-shaped intermediate portion having a fixed period, and a terminating portion having a fixed width. This is 2
A technique is disclosed in which a laser output of a value is switched and recorded at high speed.

According to the above method, the middle portion of a long mark is irradiated with the minimum power required for forming the mark by driving the laser current in a pulsed form at a constant period. Since the start and end portions are sufficiently irradiated with the laser light having a constant width, it is possible to suppress an increase in jitter at the edge portion of the mark to be formed even during direct overwriting.

Further, the positions of the start and end portions of the mark are detected when the mark length is small and when the space length before and after the mark is small, and the positions when the mark length and the space length are large are changed. By recording, the heat at the end of the recorded mark conducts through the space and affects the temperature rise process at the beginning of the next mark, or conversely, the heat at the beginning of the next recorded mark is It has become possible to compensate for a peak shift due to thermal interference that affects the temperature cooling process at the end during recording.

[0012]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. 129959 does not mention a method for obtaining the optimum positions of the start and end of the mark, and the scale of implementation of the classification of the start and end to be changed.

If the optimum method and the scale of implementation are not established, the reliability of the optimum recording itself is low, or even if the optimum recording can be realized, the excessive search for the optimum position wastes time and circuit cost. Connect.

The method of changing the positions of the start and end of the mark in accordance with the data has been invented in order to realize a high-density data. The delicate phenomenon of movement largely depends on the disc structure and the composition of the recording film, and there has been a problem that if these differ even slightly, optimum recording cannot be performed.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a method for determining the optimum positions of a mark start end portion and a mark end portion, and information capable of performing optimum recording even if the type of the disk structure or recording film composition is different. It is intended to provide a recording medium.

[0016]

In order to solve this problem, an information recording medium according to the present invention comprises a plurality of tracks formed concentrically or spirally, and irradiating a recording surface of the tracks with a light beam. A mark in which data has changed the optical characteristics of the recording film, and in an information recording medium recorded as length information of a space represented by a mark-to-mark interval, the mark start end position and the end position are defined as an input signal. The start position, the end position and / or the numerical value or representative value of the start position and / or the end position, and the method of using the start position and the end position are determined by specifying the information recording medium. Pre-recorded at the location.

In order to solve this problem, in the information recording medium of the present invention, the start position of the mark is determined by the length of the mark portion of the recording signal and the space immediately before the mark portion, and the end position of the mark is determined by: It is obtained from the length of the mark portion of the recording signal and the space portion immediately after the mark portion.

According to a first aspect of the present invention, only a first pulse or a first pulse is formed according to the length of a plurality of tracks formed concentrically or spirally and a mark portion of an original signal recorded on the track. Only two of the last pulses, the first pulse, the last pulse, and a combination of the number of one or more multi-pulses existing between them are used to drive the light beam onto the recording surface of the track using a drive pulse whose number of pulses is adjusted. An information recording medium that irradiates a mark and records information in a space between marks includes a data recording unit that records data and a specific information recording unit. The first pulse moving amount TF of the driving pulse determined by the combination of the length and the length of the space portion immediately before the mark portion is The first pulse movement amount TF is adjusted so that the reproduction jitter becomes equal to or less than a certain value. It is classified into three or more types of length, one containing only two pulses, a pulse and a last pulse, and the other containing a multipulse included between the first pulse, the last pulse, and the mark portion. Are also classified into three or more types of lengths, and a total of nine or more first pulse movement amounts T for adjusting the start of a mark.
There are at least two methods of using the value of F and the first pulse movement amount for the first pulse of the plurality of drive pulses, a method of moving the first pulse and a method of changing the width of the first pulse. The code indicating the above method is recorded in advance, and the position where the code indicating the above method is recorded is located at a position preceding the position where the value of the amount of first pulse movement is recorded in the information recording direction. An information recording medium characterized by being recorded.

According to a second aspect of the present invention, the first pulse movement amount TF includes a first reference point R1, which is a leading edge of a mark portion of an original signal to be recorded, and a starting point of a first pulse of the plurality of driving pulses. Time difference TF from edge
An information recording medium according to a first aspect, characterized by being represented by: This allows the effects of heat accumulation and thermal interference during recording,
In addition, distortion due to an equalizer at the time of reproduction is compensated at the time of recording, and recording with less jitter is realized.

According to a third aspect of the present invention, when the reference period is T, the length of the mark portion of the original signal and the length of the space portion between the mark portions are NT
(N is a positive integer from n1 to n2), and the mark portion and the space portion are respectively divided into a plurality of classes according to the lengths of the mark and the space. An information recording medium according to a first aspect, wherein a specific value is set for each of the information recording media.
Thereby, the mark start position and the mark end position are obtained more accurately.

According to a fourth aspect of the present invention, a mark portion is classified into four length types, and a space portion is also classified into four length types. Information recording medium. By finer classification, recording with less jitter is realized.

According to a fifth aspect of the present invention, there is provided an information recording medium according to the first aspect, wherein each of a mark portion and a space portion is more finely classified as the mark portion and the space portion become shorter. Since shorter ones have a higher appearance frequency, recording with less jitter is realized as compared with a case where a signal with a low appearance frequency is used as a reference signal.

A sixth aspect of the present invention is the information recording medium according to the third aspect, wherein n1 is 3, and n2 is 11.

A seventh aspect of the present invention is characterized in that mark portions are classified into three types of 3T, 4T and 5T or more, and space portions are classified into three types of 3T, 4T and 5T or more. An information recording medium according to a third aspect.

According to an eighth aspect of the present invention, a mark portion is classified into four types of 3T, 4T, 5T and 6T or more, and a space portion is classified into four types of 3T, 4T, 5T and 6T or more.
An information recording medium according to a third aspect characterized by being classified into types.

According to a ninth aspect of the present invention, only a first pulse, two pulses of a first pulse and a last pulse are provided in accordance with a plurality of tracks formed concentrically or spirally and a length of a mark portion of an original signal. Only the first pulse, the last pulse, and the number of one or more multi-pulses existing therebetween are formed by irradiating the recording surface of the track with a light beam using a drive pulse whose number of pulses is adjusted. A data recording unit and a specific information recording unit for recording information in the mark, the mark, and the space between the marks, and the specific information recording unit has a mark portion length and a mark portion immediately before the mark portion. By changing the first pulse moving amount TF of the driving pulse determined by the combination with the length of the space portion of It adjusts the formation, reproduction jitter is below a predetermined value such first pulse movement amount TF
For the mark part, only the first pulse, only the first pulse and the last pulse were included, and the first pulse, the last pulse, and the multipulse included between them were included And the space portion immediately before the mark portion is also classified into three or more length types,
A method of using the value of the first pulse movement amount TF for adjusting the start end of the mark of nine or more in total and the method of using the first pulse movement amount for the first pulse of the plurality of drive pulses is a method of moving the first pulse. There are at least two methods for changing the width of the first pulse, and a code indicating one of the methods is recorded in advance, and the position where the code indicating the above method is recorded is a value of the amount of first pulse movement. A recording / reproducing apparatus for recording / reproducing an information recording medium recorded at a position preceding the information recording direction in the information recording direction, wherein a first pulse movement amount T recorded beforehand on the information recording medium is
Means for reproducing F and a code indicating the method (1505-1)
508, 1512-1517), a means (1520) for storing a reproduced first pulse moving amount TF and a code indicating the method, a drive pulse generated by a recording data signal, and the generated drive pulse is Means (1510) for correcting the first pulse movement amount TF and the code indicating the method, and means (109, 103) for generating a light beam by the corrected drive pulse to form a space and a mark on the information recording medium. -106).

According to a tenth aspect of the present invention, the reproducing means includes an equalizer (1514), and an equalizer output amplitude for the longest mark frequency included in the same classification and an equalizer for the shortest mark frequency. Is an output amplitude of 3 dB or less.

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical information recording / reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an optical information recording apparatus according to a first embodiment of the present invention, which is a recording apparatus mainly used by a manufacturer of optical discs.

In FIG. 1, reference numeral 101 denotes an optical disk,
2 is a spindle motor, 103 is a semiconductor laser, 104
Is a collimator lens, 105 is a beam splitter, 10
6 is an objective lens, 107 is a condenser lens, 108 is a photodetector, 109 is a laser driving circuit, 110 is a pulse moving circuit, 128 and 129 are delay circuits having the same delay amount, 1
11 is a pulse generation circuit, 112 is a preamplifier, 113 is a low-pass filter, 114 is a reproduction equalizer, 115 is a binarization circuit, 116 is a PLL, 117 is a demodulation / error correction circuit, 118 is a reproduction data signal, and 119 is a power setting circuit. , 120 is a pulse position shift measuring circuit, 121 is a switch, 122, 123, and 124 are switch contacts, 125
Is a pattern signal generation circuit. Reference numeral 126 denotes a bus connecting between the pulse position shift measuring circuit 120 and the pulse moving circuit 110, and 127 denotes a memory for storing a table holding the pulse moving amount. The memory 127 previously stores two tables shown in FIG. 4B, and these two tables are modified by the present invention, and
It is rewritten into two tables shown in FIG.

The apparatus shown in FIG. 1 is an apparatus for creating the table shown in FIG. The table shown in FIG. 4A obtained by the apparatus shown in FIG. 1 is transferred to the memory of another recording apparatus shown in FIG. 27 and recorded in a predetermined recording area of all manufactured optical disks.

In FIG. 1, when an optical disk 101 is mounted, a semiconductor laser 103 and a collimator lens 10 are mounted.
4. The optical head composed of the beam splitter 105, the objective lens 106, the condenser lens 107, the photodetector 108, etc. moves to an area for obtaining the optimum positions of the mark start and end portions. The above-mentioned area is a recording area (for example, a drive test zone) provided on the innermost circumference or the outermost circumference of the disc and other than the user area where the user records data. At this time, in the switch 121,
The contact 122 is connected to the contact 123.

In the case of specializing in a recording device used by a manufacturer of an optical disk, the area for finding the optimum positions of the start and end of the mark may be the user area.

First, the peak power and the bias power are set in the laser drive circuit 109 by the power setting circuit 119. Subsequently, the output signal of the pattern signal generation circuit 125 is input to the pulse generation circuit 111 via the switch 121. The following signal flow will be described with reference to FIG.

In FIG. 2, reference numeral 201 denotes a first pattern signal which is an output signal of the pattern signal generation circuit 125;
2 is an output signal of the pulse generating circuit 111, 203 is an output signal of the pulse moving circuit 110, and 204 is a mark generated on a track of the optical disc 101 as a result of modulating peak power and bias power like the signal 203 and recording. FIG. Although 201, 202, and 203 do not occur on the same time axis, for the sake of simplicity, the corresponding portions are illustrated as being vertically arranged.

In the first pattern signal 201, 20
Reference numerals 9, 211, 213, 215, 217, and 219 denote mark portions serving as marks on the disk.
Reference numerals 214, 216, 218, and 220 denote space portions serving as spaces on the disk. The rear of 220 is again 209
Becomes That is, the first pattern signal 201
220 is a continuous pattern.

For example, when data of the Run Length Limited (2, 10) modulation method is recorded by the mark edge recording method, there are marks and spaces from the shortest 3T to the longest 11T. Here, T represents a reference period, 209 is a 6T signal serving as a mark (hereinafter, 6T mark portion), 210 is a 6T space portion, 211 is a 3T mark portion, 212 is a 6T space portion, 213 is a 6T mark portion,
214 is a 6T space portion, 215 is a 6T mark portion, 21
6 is a 4T space, 217 is a 6T mark, 218 is a 6T space, 219 is a 7T mark, and 220 is 6T.
This is the space section.

When the difference between the sum of the mark portion and the space portion for a certain period is DSV, signals 219 and 220 for setting DSV to approximately 0 only when DSV is not 0 are set.
, A signal having little DC component or low frequency component can be obtained at the time of reproduction. When a signal having many DC components or low frequency components is reproduced, the binarizing circuit 11
At 5, there is a danger of being converted into an erroneous 0, 1 signal sequence. Therefore, in the first pattern signal 201, the 7T mark section 219 and the 6T space section 220 are inserted as auxiliary signals, and the DSV is set to substantially zero. That is, the pattern signal 2
01 is the mark part 209, 211, 213, 215, 2
17, 219 total (34T) and space 2
10, 212, 214, 216, 218, 220 are configured to be equal to the sum (34T). DS
The calculation of V is performed by adding the period of the mark portion plus and the period of the space portion minus. Therefore, the DSV of the pattern signal 201 becomes 0.

The first pattern signal 201 is converted into a pulse train by the pulse generation circuit 111, and a signal 202 is output. FIG. 3 shows a state in which pulses corresponding to the respective mark portions from 3T to 11T are output from the pulse generation circuit 111.

Referring to FIG. 3, taking the 6T signal as an example, the first pulse 301 is called a first pulse, and the last pulse 304 is called a last pulse. The pulses 302, 302 between the first pulse and the last pulse are called multi-pulses, and are composed of pulses having a constant period.

The number of multi-pulses is 2 for a 6T mark.
The number of multi-pulses increases by one each time the mark becomes longer by T, such as three for the 7T mark and one for the 5T mark, and the number of multi-pulses increases each time the mark becomes shorter by T. Decrease by one. Therefore, the 4T mark is composed of only the first pulse and the last pulse, and has no multi-pulse. The 3T mark is composed of one pulse.

In this embodiment, the time length of the first pulse is 1.5T, and the time length of the last pulse is 0.1T.
Although the length of 5T and the length of the multi-pulse are set to 0.5T, depending on the configuration of the optical disk medium 101, the time length may not be set. Also, the number and cycle of the multi-pulses are not limited to the above.

Output signal 202 of pulse generation circuit 111
Is input to the pulse moving circuit 110, and a signal 203 in which the positions of the first pulse and the last pulse have moved is output. FIG. 4 shows the classification of the mark part length and the space part length when the position of the first pulse and the position of the last pulse are moved.

FIG. 4A shows the table after the correction according to the present invention has been performed, and FIG. 4B shows the table before the correction has been performed. Symbols 3S3M, 4S3M, and the like in the table of FIG. 4A are a kind of address, indicate which classification in the table, and also indicate a value assigned to the address. When viewed as an address, for example, 3S3M indicates a signal in which a 3T mark portion follows a 3T space portion. As will be described later, the position indicated by 3S3M is the value of the movement amount TF of the first pulse, and 3T after the space portion of 3T.
The value of the movement amount required when the mark portion continues is stored. The value of the movement amount TF is obtained, for example, by trial and error with respect to a certain test optical disk, and the table of FIG. 4A is completed. The contents of the completed table are stored in all the optical disks having the same composition as the test optical disk. In the left table of FIG. 4B, predetermined initial values are stored. Similarly, the table on the right side of FIG. 4B also stores the initial value before the correction of the moving amount of the last pulse.

The position of the first pulse changes according to the mark portion and the immediately preceding space portion. In this embodiment, both the mark portion and the space portion are classified into three types of 3T, 4T, 5T or more. A maximum of nine movement amounts are set according to the combination of the space portions.

FIG. 20 shows the 6T signal 201 in FIG.
An enlarged view of the mark portion 217 and a portion of the signal 202 corresponding to the mark portion 217 is shown. In this case, the 6T mark part 217
Immediately before, a 4T space section 212 exists. 4
When there is a T space part and a 6T mark part, FIG.
This applies to the 4S5M classification in the table on the left of (a). Here, the correction of the initial value of the first pulse movement amount TF written in this classification will be described.

In the apparatus shown in FIG.
25, a pattern signal 201 is generated. This pattern signal 201 is sent to a pulse generation circuit 111, and a delay circuit 129, a pulse position shift measurement circuit 120,
And also sent to the memory 127. Two tables shown in FIG. 4B are stored in the memory 127 in advance.
In the pulse position shift measuring circuit 120, the pattern signal 20
1 is stored and used for comparison with a reproduction signal during reproduction. From the pulse generation circuit 111, a pulse signal 202 necessary for recording a pattern signal is output. For example, as shown in the upper two stages of FIG. 3, the pulse generation circuit 111 responds to the rising edge of the mark portion of the pattern signal 201.
, A first pulse 301 is output, followed by a multi-pulse 302 and a last pulse 304.

The pulse signal 202 is delayed by a predetermined time (for example, 13T) by the delay circuit 128 and sent to the pulse moving circuit 110. In the memory 127, the transmitted pattern signal 201 is analyzed, and within the period of 10T or more in the past, the 18 classifications 3S3M and 3S4 shown in FIG.
M, 3S5M, 4S3M, 4S4M, 4S5M, 5S3
M, 5S4M, 5S5M, 3M3S, 4M3S, 5M3
S, 3M4S, 4M4S, 5M4S, 3M5S, 4M5
It detects whether there is any one of S, 5M5S. For example, the pattern generation circuit 1
25 to 4T space part 2 in pattern signal 201
When 16 and the subsequent 6T mark part 217 are output, the memory 127 detects that a signal belonging to the classification 4S5M has been transmitted. In response to this detection, the memory 12
7 reads the movement amount stored in the 4S5M ₀ of the table, and sends to the pulse moving circuit 110. For the first time, the initial value 4S5M ₀ of the moving amount is read out. In the pulse moving circuit 110, the first pulse of the pulse signal 202 transmitted with a delay of a predetermined time is used as the initial value of the moving amount of 4
It is moved on the basis of the S5M _0.

Using FIG. 1 and FIG. 20, the first pulse
Will be described. The pulse moving circuit 110 is
Constant pattern, for example, 4S5M (4T space section 216)
And a pattern classified by the 6T mark portion 217)
Will be sent from the delay circuit 129 soon,
Notified from the memory 127 and its classification 4S5M
₀Is received from the memory 127. Pa
Loose shift circuit 110 is sent from delay circuit 129.
Rising pulse edge of the 6T mark portion 217,
That is, counting is started at the timing of R1 in FIG.
The moving amount TF is counted. Sent from the delay circuit 128
The first pulse that has come
In the counting period, that is, the movement amount TF1.
Output.

Accordingly, as shown in FIG. 20, the first pulse movement amount TF1 is represented by a time difference from the reference R1 when the rising edge R1 of the signal 201 is used as a reference, for example. As an example, the pulse movement amount TF is 3 ns
It is about. The first pulse is moved without changing the pulse width.

The pattern signal shown in FIG.
Among the 18 classifications in (a), there are four classifications. That is, classification 3M5S appearing in period 221, classification 5S3M appearing in period 222, classification 4S5M appearing in period 223,
5M4S appearing in the period 224. Therefore, the pulse signals corresponding to the four classifications are moved by the pattern signal 201.

In accordance with the pulse thus moved, laser driving is performed, and recording of a mark is performed. FIG. 2 shows the recording marks 204. In the preferred embodiment, the pattern signal 201 (209 to 220) shown in FIG.
Is repeatedly output and recorded over one round of the track. When recording of one track is completed, one track of the track is reproduced. In the reproduction, as described later, an optical signal obtained from the photodetector 108 is converted into an electric signal, and the electric signal is processed in a preamplifier 112, a low-pass filter 113, an equalizer 114, and a binarization circuit 115.
A reproduction signal 205 is output from the value conversion circuit 115. The reproduced signal 205 is input to the pulse position shift measuring circuit 120. The pulse position shift measuring circuit 120 includes the track 1
The reproduction signal 205 from the circumference is repeatedly input, and the periods 221, 222, 223, and 224 corresponding to the classification are individually read, and the average value of each period is individually obtained.

In the pulse position shift measuring circuit 120, the averages of the periods 221, 222, 223 and 224 corresponding to the classification obtained from the pattern signal 201 recorded at the time of recording and the synchronization obtained from the reproduced signal 205 are obtained. The values are compared with each other to detect whether or not a pulse position shift has occurred. Explaining the above example, the pattern signal 2
01 and the time corresponding to the addition of the space portion 216 and the mark portion 217 and the corresponding period 22 in the reproduction signal 205.
4, and the difference between the two is determined. If there is a difference, it is determined that a pulse displacement has occurred, and the difference is sent to the memory 127. In the memory 127, the difference is, since the initial value 4S5M ₀ of the movement amount arose causing the initial value 4S5M ₀ of the moving amount increases or decreases according to the difference, performs correction of the movement amount, The corrected value is overwritten on the classification 4S5M.

In the above description, one feedback loop (11
0, 109, 108, 112, 115, 120, 12
Although the value corrected by 6) is overwritten in the classification 4S5M, feedback may be performed a plurality of times. As described above, the first pulse movement amount TF in FIG. 20 is corrected.

Similarly, the moving amount of the last pulse changes according to the mark portion and the space portion immediately after. In this embodiment, both the mark portion and the space portion are classified into three types of 3T, 4T, and 5T or more. Nine types of moving amounts are set by a combination of the mark part and the space part. The last pulse corrects the pulse movement amount TL in the same manner as the first pulse.

FIG. 21 shows the 6T mark portion 215 in the pattern signal 201 of FIG.
The enlarged view of the part is shown. The last pulse movement amount TL is corrected in the same manner as described above, but the last pulse movement amount TL is a time interval from the new reference R2 shifted 2T forward from the end edge of the mark portion to the end edge of the last pulse. In other words, this time interval is corrected by the above-described feedback loop described for the first pulse. TL is about 13 ns in the present embodiment. Here, even if the value of TL changes, the width of the last pulse does not change, and in the present embodiment, the time axis is moved with the same width.

In FIG. 2, reference numeral 206 denotes an output signal of the pulse moving circuit 110 obtained by using the corrected movement amount table (FIG. 4A), 207 denotes a mark recorded by the output signal, and 208 denotes a mark recorded by the output signal. , Indicates a reproduced signal reproduced by the mark. The reproduced signal 205 obtained by using the table of the movement amount before the correction (FIG. 4B) has an error from the original pattern signal 201, but the table of the movement amount after the correction (FIG. The reproduced signal 208 obtained by using a)) is the original pattern signal 201.
And there is almost no error.

In the above description, the amount of movement was corrected for four of the 18 classes using the pattern signal 201 of FIG. 2, but the remaining classes were corrected using different pattern signals. Done. Pattern signal 1 in FIG.
Using 101, classifications 4M5S, 5S4M, 3S5M,
The movement amount is corrected for 5M3S. Using the pattern signal 1201 of FIG. 12, classification 4M4S, 3M3S,
The movement amount is corrected for S4M and 3S3M. FIG.
4M3S, 4S
The movement amount is corrected for 3M. Using the pattern signal 1401 in FIG. 14, the movement amount is corrected for the classifications 3M4S and 3S4M.

The classifications 5M5S and 5S5M are as follows.
A certain initial value may be determined, or the movement amount is corrected using the pattern signal 2801 in FIG. In addition,
For the classifications 5M5S and 5S5M, the correction of the movement amount is the longest period for both the mark and the space and is the class with the least influence of thermal interference. Therefore, each delay amount is small and should be used as a reference standard for determining other delay amounts. Therefore, it is preferable to perform the correction before correcting other classifications.

The classification of the signal when changing the moving amount of the first pulse and the last pulse is roughly determined by the following three factors.

The first factor is the influence of heat accumulation on the recording film when a mark is recorded, and the heat at the end of the recorded mark is conducted through the space to affect the temperature rise at the start of the next mark. Conversely, the difference between the magnitude of the thermal interference itself, in which the heat at the beginning of the next recorded mark affects the cooling process at the end of the previous mark, and the magnitude due to the combination of the mark and space. .

The effect of heat accumulation on the recording film can be reduced by providing a multi-pulse between the first pulse and the last pulse and irradiating only the minimum power required for forming a mark. For simplicity, it is composed of pulses of a fixed period and cannot be completely removed.

The magnitude itself of the effects of heat accumulation and thermal interference often depends on the structure of the optical disc 101, the characteristics of the recording film, the recording pulse, the linear velocity at the time of recording on the optical disc 11, the shortest mark length, and the like. Conversely, by optimizing them, the size can be reduced to some extent.
Therefore, as a first factor, attention is paid to a difference in size due to a combination of a mark and a space.

As is clear from FIG. 4A, in this embodiment, nine classifications are performed for the first pulse. A method of performing classification for changing the movement amount of the first pulse and the last pulse based on the first factor will be described with reference to FIGS. FIG. 5 shows 11T
FIG. 9 is an explanatory diagram of a method for examining the front space dependency of the amount of extension at the start position of a mark.

In FIG. 5, an original signal 500 is a binary signal waveform of a recording signal used for recording, a mark 501.
Represents a mark recorded on a recording medium, and a reproduction signal 502 represents a binary signal waveform of a reproduction signal reproduced from the recorded mark. The original signal 500, the mark 501, and the reproduction signal 502 have an 11T mark in a sufficiently long space (S ×
This shows a case where recording is performed with a space T), and the interference between marks is minimized by a long space.

Here, the space ts1 in the original signal 500 and the space tm in the reproduced signal 502
Ideally, the eleven time intervals would be equal. To approach this ideal, the positions of the first pulse and the last pulse are moved. Regarding how much to move, if attention is paid only to the mark start end position, it can be classified into approximately three groups. The method of classifying the mark start position will be described using the original signal 520, the mark 521, and the reproduced signal 522.

The original signal 520 is a binarized signal waveform used for recording, and the space ts21 sandwiched between the 11T marks is smaller than that of the original signal 500 described above. In the result mark 521, 1
The heat at the end of the 1T mark 524 is conducted through the space 525 and transmitted to the next 11T mark 526, so that the start end of the 11T mark 526 is extended and the net length of the 11T mark 526 is increased by α2.

As a result, the time interval between the space ts21 in the original signal 520 and the space ts31 in the reproduced signal 522 becomes shorter, and a correct reproduced signal cannot be obtained. Here, in order to obtain a correct reproduction signal, elongation of the starting position of the 11T mark 526 is expected, and
The rising position of the mark portion tm22 in the original signal 520 may be delayed in advance. Since the amount of delay depends on the length of the space ts21, the space t
The length of s21 is changed from 3T to 11T at every time T, and 11T marks are recorded, and each edge interval is 527.
Is measured.

FIG. 6 is a graph showing the result of the measurement shown in FIG. In the graph, the horizontal axis represents a value obtained by changing the space ts21 in the original signal 520 from 3T to 11T, and the vertical axis represents a value obtained by adding the mark portion tm20 and the space portion ts21 in the original signal 520 and subtracting the edge interval r 527 from the value obtained by adding the mark portion tm20 and the space portion ts21. Is shown. 3T,
In a short space length such as 4T, the starting end position of the 11T mark 526 extends forward due to thermal interference.

FIG. 7 is a diagram in which, based on the results of FIG. 6, groups of spaces having the same value on the vertical axis are grouped together. Those with large differences were classified differently. As a result, it is classified into three sections: a 3T space section, a 4T space section, and a 5T or more space section.

FIG. 8 is a diagram showing the classification of FIG. 7 on a map. The hatched portion indicates the location where the measurement was performed, and the thick line indicates the classification.

As shown in FIG. 5, the extension of the starting end of the 11T mark differs depending on the immediately preceding space length.
It is divided into three classifications of T or more.

FIG. 9 shows a series of evaluations from FIG. 5 to FIG.
It is an example of the result performed for all the rows and columns of the map. From FIG. 9, it is desirable to classify the movement amount of the first pulse into a total of three or more types of 3T, 4T, 5T or more for both the mark portion and the space portion.

The moving amount of the last pulse changes according to the mark portion and the space portion immediately after. However, in the present embodiment, for the same reason as the first pulse, both the mark portion and the space portion have 3T, 4T, 5T or more. It is desirable to classify into three or more types.

As in the present embodiment, when the measurement results are almost the same between adjacent cells on the map, that is, from 5T to 11T, the circuit classification of the pulse moving circuit 110 is reduced by the same classification. Can save money.

Further, as in the present embodiment, focusing on the size difference due to the combination of the mark and the space, the case where the space is 4T and the case of 3T are classified differently from the case where the space is 5T or more. This makes it possible to control the amount of movement of the first pulse and the amount of movement of the last pulse according to the pattern, and as a result, it is possible to realize recording with less jitter.

Further, paying attention to the size difference due to the combination of the mark and the space, the case where the space is 4T and the case of
The first and second cases can be classified into one category, so that the first pulse movement amount and the last pulse movement amount can be controlled according to the pattern.

The second factor is the characteristic of the reproduction equalizer 114. The characteristics of the reproduction equalizer 114 depend on the light spot size, the shortest mark length, and the like. The light spot size is determined by the wavelength of the semiconductor laser 103 and the numerical aperture of the objective lens 106.

A method for performing classification for changing the moving amount of the first pulse and the last pulse based on the second factor will be described with reference to FIG.

FIG. 10 schematically shows the frequency characteristics of the reproduction equalizer 114. This represents the amplitude ratio of the output signal to the input signal of the equalizer. The horizontal axis is the signal frequency, and the vertical axis is the logarithmic representation of the output amplitude of the reproduction equalizer 114. On the horizontal axis, 3T signal, 4T signal, 5
The frequency of the T signal and the 11T signal are schematically shown. An equalizer characteristic is set so as to increase the output amplitude in order to correct the attenuation of the optical frequency characteristic that a signal having a higher frequency, such as a 3T signal, has a smaller mark and therefore has a smaller reproduced amplitude due to a smaller mark. This includes a high pass filter (High Pass Filter) and a band pass filter (Band Pass Filt) that has a peak at a frequency slightly higher than 3T.
er) or a combination thereof with an amplifier.

Therefore, the difference between the output amplitude when the space or the mark is a high-frequency signal such as 3T and the output amplitude when the space or the mark is a low-frequency signal such as 11T, that is, the slope of the characteristic curve is determined by the shortest mark length. The shorter, the larger.
Accordingly, for example, the difference between the output amplitude at the frequency of 5T and the output amplitude at the frequency of 11T also increases.

In the classification for changing the movement amount of the first pulse and the last pulse, if a mark having a large difference in output amplitude is put in the same classification, the influence of heat accumulation and thermal interference of the recording film is eliminated. Even when recording is performed in such a manner, a correct edge position cannot be reproduced due to the reproduction equalizer 114.

Therefore, it is desirable that the difference between the output amplitude characteristics of the reproduction equalizer 114 of a plurality of marks included in the same classification is as small as possible.

Among the plurality of marks included in the same classification, the ratio between the output amplitude of the reproduction equalizer 114 for the frequency of the longest mark and the output amplitude of the reproduction equalizer 114 for the frequency of the shortest mark is 3 dB or less. Is desirable. 3 dB is a numerical value relatively frequently used as a classification value when dealing with frequency characteristics, and its real value means a square root of 2. That is, when a signal having the same amplitude is input at any frequency, the amplitude ratio between the input signal and the output signal of the equalizer is the difference of the square root of 2. By setting the output amplitude ratio to 3 dB or less as in this embodiment as a limit value to be treated as the same classification, distortion errors due to the equalizer during reproduction are reduced, and recording and reproduction with less jitter can be realized.

The wavelength of the semiconductor laser 103 is 650.
nm, the numerical aperture of the objective lens 106 is 0.6, the shortest mark length is 0.595 μm, and the mark edge recording is performed under the conditions of the RLL (2, 10) modulation method.
It is not desirable to classify a mark shorter than T, that is, a 4T mark or a 3T mark into the same classification as the 11T mark, and even when the circuit scale of the pulse shift circuit 110 is taken into consideration,
It is desirable to classify 5T marks or more into the same classification as in this embodiment, or to classify 6T marks or more into the same classification. In the case of the present embodiment, T is about 30 ns, 3T is about 90 ns, and 11T is about 330 ns.

The third factor is the circuit scale of the pulse shift circuit 110, the setting accuracy in the pulse shift, and the limitations on the circuit scale of the pattern signal generating circuit 125 and the memory 127. From the above two factors, it is sufficient that the mark or the space having a large difference between the heat accumulation and the thermal interference should be classified differently, and the mark having a large output amplitude ratio of the reproduction equalizer should be classified differently. As the number of registers to be set increases, the circuit scale of the pulse shift circuit 110 increases. As the number of registers to be set increases, the number of patterns for determining the values to be set in the increased registers also increases, and the pattern signal generation circuit 1
The circuit scale of 25 also increases. In addition, regardless of whether the setting is performed in the factory or in the market, the time required for the setting increases, and the consumption of recording tracks required for the setting also increases. Therefore, from the third viewpoint, it is desirable that the classification be minimized.

By classifying the 5T mark or more into the same classification as in this embodiment, the circuit scale of the pulse shift circuit 110 and the circuit scale of the pattern signal generation circuit 125 can be reduced.

As described above, several factors are involved in determining the optimum classification. In the present embodiment, the classification is performed as shown in FIG. 4 in consideration of the three factors.

Before the recording of the pattern signal, FIG.
As shown in (1), a predetermined initial value is set. This initial value may be a value empirically obtained individually or may be the same value. As an example of the same value, for example, in the left table of FIG. 4B, the value of the first pulse movement amount in the case of 5S5M, for example, 1n
may be s. In the table on the right side of FIG.
The value set in M5S may be used. In this case,
As shown in FIG. 3, the value set to the classification 5S5M is determined so that the time length between the first pulse 301 and the multi-pulse 302 becomes 0.5T, and the multi-pulse 303 is determined.
The value set to the classification 5M5S is determined so that the time length between the last pulse 304 and the last pulse 304 becomes 0.5T. Note that the values set for the class 5S5M and the class 5M5S may be obtained by other methods. An example is shown in FIG. 28, reference numeral 2801 denotes a 6T single cycle signal which is an output signal of the pattern signal generation circuit 125, and 2802 denotes a pulse generation circuit 1
11, 2803 is the output signal of the pulse shift circuit 110, 2804 is the peak power like the signal 203,
As a result of recording by modulating the bias power, the optical disk 1
It is a schematic diagram of a mark generated on track No. 01.
Although 2801, 2802, and 2803 are not on the same time axis, for the sake of simplicity, the corresponding portions are illustrated as being vertically arranged. The pattern signal of FIG. 28 is a single-period signal in which a mark and a space are continuous at intervals of 6T,
5S5M, 5M5 out of the 18 classifications shown in FIG.
There are two classes of S. In FIG. 28, the signal 280
Laser driving is performed according to No. 3, and mark recording is performed. In a preferred embodiment, pattern signal 2801 shown in FIG. 28 is repeated and recorded over one track. When recording of one track is completed, one track of the track is reproduced. For reproduction, an optical signal obtained from the photodetector 108 is converted into an electric signal, processed in the preamplifier 112, the low-pass filter 113, and the equalizer 114, and the reproduced signal 280 is output from the equalizer 114.
5 is output and input to the asymmetry measurement circuit 130 and the binarization circuit 115. The binarization circuit 115 adjusts the slice level signal 2809 so that the interval between the output level corresponding to the mark and the output level corresponding to the space becomes equal in the output signal of the binarization circuit. Is the asymmetry measurement circuit 1
30 is input. The asymmetry measuring circuit compares the average value of the minimum value 2810 and the maximum value 2811 of the reproduced signal 2805 with the slice level signal 2809. It is determined that this shift is caused by the positional shift between the first pulse and the last pulse, and, for example, the first pulse and the last pulse move in the opposite direction by the same time according to the sign of the difference between the two. to, to correct the initial value 5S5M ₀ and 5M5S ₀ of the movement amount, it overwrites the modified values in the memory 127. In the above description, one feedback loop (110, 109, 1
08, 112, 114, 115, 130, 126), the values 5S5M and 5M5S have been overwritten, but feedback may be performed multiple times. As described above, 5S5M and 5M5S are used so that the 6T mark is recorded with the correct length.
Is determined. By making the physical length of the reference mark correct, marks of other classifications also have the correct length, and recording with less jitter can be realized.

The output signal 203 of the pulse shift circuit 110 is input to the laser driving circuit 109, and the signal 203 emits light at the peak power during the H level time and emits light at the bias power during the L level time.
Are formed as shown in FIG.

At the time of reproduction, the laser light emitted from the semiconductor laser 103 is collimated by a collimator lens 104, then enters a beam splitter 105, and the light transmitted through the beam splitter 105 is condensed by an objective lens 106. Irradiates the optical disc 101 as a light spot.

The light reflected by the optical disk 101 is condensed by the objective lens 106, and is again focused on the beam splitter 105.
The light reflected by the beam splitter 105 is condensed by a condenser lens 107 and is imaged on a photodetector 108.

In the photodetector 108, the light quantity is converted into an electric signal, input to the preamplifier 112 and amplified. Further, the output signal of the preamplifier 112 is cut off by a low-pass filter 113 to a high-frequency signal, waveform equalization is performed by an equalizer 114, and binarization is performed by a binarization circuit 115 from a predetermined slice level. The signal 205 converted into a column is output and input to the pulse position shift measuring circuit 120. Pulse displacement measurement circuit 1
20 is a specific edge interval 221 in the signal 205;
222, 223, and 224 are measured.

The edge interval 221 in FIG.
If it is longer than T, it is connected via bus 126 to FIG.
The setting of the last pulse movement amount 3M5S of (a), from the current value 3M5S _0, reduced by the amount of deviation. Similarly,
When the edge interval 222 is longer than 9T regular via the bus 126, the first pulse movement amount 5S3M in FIG. 4 (a), from the current value 5S5M _0, increased by the amount of deviation. Similarly, for the edge intervals 223 and 224, the value of 4S5M and the value of 5M4S
Update the value of.

When the update of the four settings is completed, the first
Is recorded, and the edge interval is measured. The same cycle is repeated for all four edge intervals at the same time until the difference between the normal value and the measured edge interval becomes equal to or smaller than a certain value. When measuring the edge interval, for example, if the edge interval is 221, the edge that is not moved is the falling edge of the 6T mark portion 209,
The space immediately after is the 6T space 210. In the case of the edge interval 222, the edge that is not moved is the rising edge of the 6T mark portion 213, and the immediately preceding space is the 6T space 212.

The mark portion and the space portion sandwiching these edges which are not moved are called reference signals. If the edge position between the reference signals changes in synchronization with the edge to be moved, correct setting cannot be performed. Therefore, at least the edge position sandwiched between the reference signals must not change in synchronization with the edge to be moved.

Even if the edge position sandwiched by the reference signals does not change in synchronization with the edge to be moved, for example, if the shortest mark is the reference signal, any of the shortest marks is set as follows: It is necessary to change the reference mark so that it does not change in synchronization. It is desirable that the reference mark be fixed in consideration of the variation in the setting.

If the reference signal is included in the same classification as the longest signal, the reference signal for all the settings in FIG. 4A can be made the same, and the combination of the mark portion and the space portion can be more accurate. The mark start position and the mark end position can be obtained at the same time.

Further, heat accumulation in the classification for changing the moving amount of the first pulse and the last pulse,
From the viewpoint of thermal interference, there is a slight difference in the amount of change in the edge position of the mark even in the same classification as the longest signal. Therefore, as in the present embodiment, if the reference signal is included in the same classification as the longest signal and has a high appearance frequency, the appearance of inaccurate edge positions can be reduced as a whole.

Similarly, from the viewpoint of the output amplitude of the reproduction equalizer 114 in the classification for changing the movement amount of the first pulse and the last pulse, even in the same classification as the longest mark, the difference in the output amplitude of the reproduction equalizer is slight. Exists. Therefore, if the reference signal is a mark with a high appearance frequency included in the same classification as the longest mark as in the present embodiment, the appearance of incorrect edge positions can be reduced as a whole in the recording / reproducing system. it can.

By reducing the appearance of inaccurate edges as a whole, demodulation and demodulation can be performed during actual data recording.
The probability that the error is corrected by the error correction circuit 117 increases.

Normally, the shorter the signal, the higher the appearance frequency and the greater the difference in the output amplitude of the reproduction equalizer. Therefore, the determination of the reference mark is a trade-off between the two. However, the reference mark is a 6T mark in consideration of the characteristics of the reproduction equalizer.

Note that the initial values 3S3M ₀ and 3
Value of M3S ₀ or the like, the reference marks are to choose to be recorded at the correct length, depending on the configuration of the optical disc medium 101 may be using different initial values.

When the recording of the first pattern signal is completed, the second pattern signal is recorded. In FIG. 11, 110
1 is the second output signal of the pattern signal generation circuit 125
, 1102 indicates an output signal of the pulse generating circuit 111, and 1103 indicates an output signal of the pulse moving circuit 110. Reference numeral 1104 denotes a mark recorded by the signal 1103 and generated on a track of the optical disc 101.
Hereinafter, the settings of the first pulses 5S4M and 3S5M and the last pulses 4M5S and 5M3S in FIG. 4A are updated in the same manner as in the case of the first specific pattern.

When the recording of the second pattern signal is completed, the third pattern signal is recorded. In FIG.
1 is the third output signal of the pattern signal generation circuit 125;
, 1202 indicates an output signal of the pulse generating circuit 111, and 1203 indicates an output signal of the pulse moving circuit 110. Reference numeral 1204 denotes a mark recorded by the signal 1203 and generated on a track of the optical disc 101.
In FIG. 12, 10T of 1210 to 1211 (6T space / 4T mark) and 10T of 1212 to 1213 (4T mark)
(Space, 6T mark) have the same time length and appear as a continuous waveform.
1 has the same length as the next signals to be measured 1212 to 1213, making it difficult to accurately separate and measure the signals to be measured. Therefore, when the lengths of the two 10Ts are almost the same, the jitter can be measured by using the fact that the jitter is minimized. Except for the above, the first pulse 4S4 shown in FIG.
The settings of M, 3S3M, and last pulses 4M4S, 3M3S are updated.

When the recording of the third pattern signal is completed, the fourth pattern signal is recorded. In FIG.
Reference numeral 1 denotes an output signal of the pattern signal generation circuit 125,
Are the output signals of the pulse generating circuit 111, and 1303 is the output signal of the pulse moving circuit 110. Reference numeral 1304 denotes a mark recorded by the signal 1303 and generated on a track of the optical disc 101.
Hereinafter, the settings of the first pulse 4S3M and the last pulse 4M3S in FIG. 4A are updated in substantially the same manner as in the case of the first specific pattern.

When the recording of the fourth pattern signal is completed, the fifth pattern signal is recorded. In FIG. 14, 140
1 is the fifth output signal of the pattern signal generation circuit 125
, 1402 denotes an output signal of the pulse generating circuit 111, and 1403 denotes an output signal of the pulse moving circuit 110. Reference numeral 1404 denotes a mark recorded by the signal 1403 and generated on a track of the optical disc 101.
Thereafter, in the same manner as in the case of the fourth specific pattern, the first pulse 3S4M and the last pulse 3S4M shown in FIG.
Update the settings of M4S.

As described above, the start position of the mark is obtained from the length of the mark to be recorded and the space before the mark, and the end position of the mark is obtained from the length of the mark to be recorded and the space after the mark. This makes it possible to compensate for the effects of heat accumulation and thermal interference during recording and distortion due to an equalizer during reproduction during recording, thereby realizing recording with less jitter.

Furthermore, the start and end positions of the mark are recorded from the first pattern to the fifth pattern, and the first edge and the fifth edge are compensated so that the deviation between the specific edge of the pattern and the normal length is reduced. The first pulse and the last pulse according to the pattern can determine the optimum amount of movement for any pattern other than the first to fifth patterns, and the mark is recorded at the correct position when recording data Thus, recording with less jitter can be realized.

Further, when the difference between the reference signal, the signal to be measured, and the sum of the mark portion and the space portion for a certain period is DSV, the pattern of this embodiment can be used only when DSV is not 0. It is composed of a simple pattern of a signal for making it approximately zero.

For example, in 201 in FIG. 2, the total of the mark portion is 34T, and the total of the space portion is 34T. By incorporating two types of marks to be measured having different edge intervals in one pattern, the number of patterns can be reduced from the small number of patterns shown in FIG.
(A) can be set, the time required for setting,
Recording tracks required for setting and pattern signal generation circuit 1
25 circuit scales can be saved. Pattern signal generation circuit In this embodiment, the pulse position shift measurement circuit 120
Measures the position shift of the output signal of the binarization circuit 115, detects the edge interval or the jitter of the edge interval, corrects the table stored in the memory 127 based on the measurement result, and outputs the corrected movement amount as a pulse. A signal is sent to the moving circuit 110 to move the first pulse and the last pulse. Apart from this configuration, for example, the output signal of the binarization circuit 115 is connected via a GPIB or the like to a measuring instrument such as a time interval analyzer for measuring a time interval or jitter, and the time interval is further provided via a GPIB or the like. Connect the analyzer to the personal computer, and connect the SCSI
A signal may be sent to the pulse shift circuit 110 via the above. In this case, the recording device does not need to include the pulse position shift measuring circuit 120, and the recording device can be simplified accordingly.

In the present embodiment, the first pulse and the last pulse are moved in accordance with the combination of the mark and the space. However, the recording method for changing the pulse width of the first pulse and the last pulse can be performed in the same manner. The pulse width can be optimized.

FIG. 22 shows the 6T mark portion 213 in the signal 201 in FIG. 2, the portion corresponding to the 6T mark portion 213 in the signal 202, and the pulse in the case where the space length before the 6T mark is 4T instead of 6T. An example of optimization for changing the width is shown.

The width of the first pulse changes according to the mark portion and the immediately preceding space portion. In the present embodiment, both the mark portion and the space portion are classified into a total of three types of 3T, 4T, and 5T or more. A maximum of nine movement amounts are set according to the combination of the space portions.

The amount of movement of the rising edge of the first pulse is represented by TF with reference to the rising edge of the signal 201, for example. The falling edge of the first pulse does not move. In the 6T mark portion 213, since the front space portion is 6T, the classification is 5S5M, and TF1 is about 1 ns. When the preceding space is 4T, the classification of the moving amount of the rising edge of the first pulse is 4S5M, and TF2 is about 3 ns. The front space is 3
At T, the classification of the first pulse width is 3S5M, and TF3 is about 5 ns. Here, even if the value of TF changes, the falling edge of the first pulse does not change.
The first pulse width changes.

FIG. 23 shows 6T signal 201 in FIG.
The mark part 213, a portion corresponding to the 6T mark part 213 in the signal 202, and an example of optimization for changing the pulse width when the space length behind the 6T mark is 4T and 3T instead of 6T will be described.

The moving amount of the rising edge of the last pulse is represented by TL, for example, two clocks before the falling edge of the signal 201. The falling edge of the last pulse does not move. In the 6T mark part 213, since the rear space part is 6T, the classification is 5M5S, and the TL
1 is about 13 ns. When the rear space portion is 4T, the classification of the moving amount of the rising edge of the last pulse is 5M4S, and TL2 is about 11 ns. When the rear space is 3T, the classification of the last pulse width is 5M3S, and TL3 is about 9 ns. Where TL
, The rising edge of the last pulse does not change, and the last pulse width changes.

In addition to changing the position and width of the pulse,
There are a plurality of methods for controlling the mark start position and the mark end position, such as changing the light emission power of a specific pulse. Therefore, describing a control method or determining a code indicating a control method together with a table of TF or TL in advance and recording the control method code together with the table is necessary for accurate recording. is important.

Hereinafter, an information recording medium and an optical information recording apparatus according to different embodiments of the present invention will be described with reference to the drawings. FIG. 15 is a block diagram of an information recording medium and an optical information recording device according to the second embodiment of the present invention.

In FIG. 15, reference numeral 1501 denotes an optical disk;
1502 is a spindle motor, 1503 is a semiconductor laser, 1504 is a collimator lens, 1505 is a beam splitter, 1506 is an objective lens, 1507 is a condenser lens, 1508 is a photodetector, 1509 is a laser drive circuit,
1510 is a pulse moving circuit, 1528 and 1529 are delay circuits, 1511 is a pulse generation circuit, and 1520 is a memory. 1512 is a preamplifier, 1513 is a low-pass filter, 1514 is a reproduction equalizer, 1515 is a binarization circuit, 1516 is PLL, 1517 is a demodulation / error correction circuit, 1518 is a reproduction data signal, and 1519 is a power setting circuit.

FIG. 16 is a plan view of the optical disk 1501. In FIG. 16, reference numeral 1601 denotes optimal position information of the start and end of the mark determined in the first embodiment;
That is, this is an area in which the two corrected tables shown in FIG. 4A are recorded, and is a state in which a pit row or a mark and a space are formed on the innermost circumference of the disc at the stage of shipment from the producer. It is composed of These two corrected tables are created by the manufacturer of the optical disk by the apparatus shown in FIG. 1 and stored in advance in all the optical disks. The user obtains the optical disk on which the two corrected tables are stored, and uses the optical disk with the apparatus shown in FIG.

When the optical disk 1501 is loaded, an optical head including a semiconductor laser 1503, a collimator lens 1504, a beam splitter 1505, an objective lens 1506, a condenser lens 1507, a photodetector 1508, etc. After the above operation is completed, it moves to the area 1601 where the optimal position information of the mark start and end portions is recorded, and reproduces the area. The reproduced data is data including the two corrected tables shown in FIG. 4A and stored in the memory 1520.

Here, mass production of an optical disk in which a corrected table is stored by a manufacturer will be described. If the area 1601 of the optical disk 1501 is a pit row having irregularities, the optimum positions of the mark start and end portions are determined by, for example, the method of the first embodiment, and the two corrected positions shown in FIG. After the table is created, the contents of the two corrected tables are created by performing laser cutting when the stamper that is the basis of the optical disk 1501 is created.

FIG. 27 shows such a master cutting device. 27, reference numeral 2701 denotes a memory, 2702 denotes an adjustment method information generation unit, 2703 denotes a recording signal generation unit,
Reference numeral 04 denotes an optical modulator, 2705 denotes a laser, 2706 denotes a lens, 2708 denotes a glass master on which a photosensitive material 2707 is applied, 2709 denotes a turntable, and 2710 denotes a motor.

As shown in FIG. 27, the memory 2701 stores two modified tables shown in FIG. 4A obtained by the apparatus shown in FIG. First, information on the adjustment method of the first pulse and the last pulse is output from the adjustment method information generation unit 2702, and
From 701, the contents of the two modified tables are output. In a recording signal generation unit 2703, modulation, ECC addition, scrambling, and the like are performed, and the data is converted into binary data for recording. Solid-state laser 270 oscillating at a wavelength such as ultraviolet light
The laser beam output from 5 is an optical modulator 2704,
The output power is modulated by the output signal of the recording signal generation unit 2703, and the light is irradiated on the photosensitive material 2707 applied to the glass master 2708 via the objective lens 2706. At this time, the binary recording is realized by the presence or absence of irradiation.
Here, the contents of the two tables stored in the memory 2701 are recorded inside the area where the user records data, and the information of the adjustment method is recorded further inside the information of the table contents.

Thereafter, the portion irradiated with the ultraviolet laser is melted, and a metal such as nickel is sputtered, whereby a metal stamper having uneven pits is formed.
A disk substrate is formed using the metal stamper as a mold, and a recording film or the like is formed on the disk substrate. One disc is created by bonding two substrates on each of which a recording film is formed on at least one side.

Returning to FIG. 15, the laser light emitted from the semiconductor laser 1503 is collimated by the collimator lens 1504, and then enters the beam splitter 1505.
The light transmitted through the beam splitter 1505 is condensed by the objective lens 1506 and irradiated on the optical disc 1501 as a light spot.

The light reflected by the optical disk 1501 is condensed by the objective lens 1506, and is again focused on the beam splitter 1
Proceeding to 505, the light reflected by the beam splitter 1505 is condensed by a condenser lens 1507 and
An image is formed at 508.

In the photodetector 1508, the light quantity is converted into an electric signal, input to the preamplifier 1512 and amplified. Further, the output signal of the preamplifier 1512 is cut off by a low-pass filter 1513 in a high-frequency signal, and is equalized by an equalizer 1514.
At 5, binarization is performed from a predetermined slice level, and 0,
The signal converted into one signal sequence is output. A clock is extracted from the output signal of the binarization circuit 1515 by a PLL 1516, and an output signal synchronized with the clock is input to a demodulation / error correction circuit 1517, where errors in data that can be demodulated and correctable are corrected, and a reproduced data signal is corrected. 1518.

The contents of the two tables, which are the reproduction data signal 1518, and the information on the adjustment method are stored in the memory 1520. Optimal movement amount information of the mark start and end portions from the memory 1520 is input to the pulse shift circuit 1510 via the bus 1521.

At the time of recording, first, the power setting circuit 151
9, the peak power and the bias power are set in the laser drive circuit 1509. The following signal flow will be described with reference to FIG.

In FIG. 17, reference numeral 1701 denotes a recording data signal which is an input signal to the pulse generation circuit 1511;
2 indicates an output signal of the pulse generation circuit 1511, and 1703 indicates an output signal of the pulse shift circuit 1510. Reference numeral 1704 denotes a mark generated on a track of the optical disc 1501 by recording by modulating the peak power and the bias power like the signal 1703. Although 1701, 1702, and 1703 are not on the same time axis, corresponding portions are illustrated as being vertically arranged for easy understanding.

In the recording data signal 1701, 170
Reference numerals 6, 1708, and 1710 denote mark portions that become marks on the disk, and 1707, 1709, and 1711 denote space portions that become spaces on the disk.

For example, when data of the RLL (2, 10) modulation system is recorded by the mark edge recording system, the shortest 3T
And the longest mark and space up to 11T. Here, T represents a reference cycle, and 1706 is 6
T mark part, 1707 is 6T space part, 1708 is 4
T mark part, 1709 is 4T space part, 1710 is 6
The T mark part 1711 is a 6T space part.

The recording data signal 1701 is converted into a pulse train by the pulse generation circuit 1511 and a signal 1702 is output. FIG. 18 shows the result of changing each mark from 3T to 11T into a pulse train.

In FIG. 18, for example, a pulse 1801 at the head of a 6T signal is called a first pulse.
The last pulse 1804 is called a last pulse, and a pulse 180 located between the first pulse and the last pulse.
2 and the pulse 1803 are called multi-pulses, and are composed of pulses having a constant period.

The number of multi-pulses is 2 for a 6T mark.
The number of multi-pulses increases by one each time the mark becomes longer by T, such as three for the 7T mark and one for the 5T mark, and the number of multi-pulses increases each time the mark becomes shorter by T. Decrease by one. Therefore, the 4T mark is composed of only the first pulse and the last pulse, and has no multi-pulse. The 3T mark is composed of one pulse. .

In this embodiment, the length of the first pulse is 1.5T, and the time length of the last pulse is 0.5T.
T and the length of the multi-pulse are set to 0.5T. However, depending on the configuration of the optical disk medium 1501, the length may not be the time length.

As described above, the signals 1701 and 170
2 are not on the same time axis, but the difference between the rising edge of the signal 1701 and the rising edge of the first pulse of the signal 1702 is the same for any mark portion, and the falling edge of the signal 1701 and the last pulse of the signal 1702 are equal. The difference from the falling edge is equal for any mark portion.

Output signal 170 of pulse generation circuit 1511
2 is input to the pulse shift circuit 1510, and the signal in which the positions of the first pulse and the last pulse have been shifted is the signal 1
703 is output. FIG. 19 shows a table stored in the memory 1520. This table is the same as the table in FIG. 4A, and has a mark portion length when moving the position of the first pulse and the position of the last pulse.
Indicates the classification of the space manager.

The moving amount of the first pulse changes according to the mark portion and the immediately preceding space portion. In the present embodiment, both the mark portion and the space portion are classified into three types of 3T, 4T, 5T or more, and the mark portion is classified into three types. A maximum of nine movement amounts are set by a combination of the section and the space section.

Similarly, the moving amount of the last pulse changes according to the mark portion and the space portion immediately after. In this embodiment, both the mark portion and the space portion are classified into three types of 3T, 4T, and 5T or more. , A maximum of nine movement amounts are set by a combination of a mark portion and a space portion. The method of determining the classification is the same as in the first embodiment.

Output signal 170 of pulse shift circuit 1510
3 is input to the laser drive circuit 1509 and the signal 1703
1 emits light at the peak power during the H level time and emits light at the bias power during the L level time in FIG.
7, a mark row as shown at 1704 is formed.

As described above, according to the present embodiment, data for changing the mark start position and the mark end position according to an input signal, which is recorded in a specific area of an optical disk, is reproduced, and the recorded data is reproduced by a recording apparatus. By setting, optimum recording can be performed even if the type of the optical disk such as the disk structure or the recording film is different.

Note that the optimum position information of the mark start and end portions recorded in a specific area does not have to be obtained for every disk, and if the variation among the disks is small, the same disk structure, A value obtained from disks having the same recording film composition may be recorded as a representative value.

To further improve the jitter,
Even when the optimum positions of the start and end of the mark are to be obtained again when recording data, if the representative movement amount information is recorded in a specific area as in the optical disc of the present embodiment, the information may be obtained. If the optimum movement amount is obtained with the state as a default, the time required for optimization can be saved.

In this embodiment, both the mark portion and the space portion are classified into three types of 3T, 4T, and 5T or more. However, the classification is determined in the same manner as in the first embodiment. As long as the optimum movement amount information of the pulse and the last pulse is described on the disk, other classifications such as classification into 3T, 4T, 5T and 6T or more according to various conditions may be used. FIG. 24 shows a mark portion,
FIG. 4 shows a classification diagram of pulse movement in a case where the space portion is classified into a total of four types of 3T, 4T, 5T, and 6T or more. By increasing the number of classifications, the moving amount of the first pulse and the moving amount of the last pulse can be finely controlled according to the pattern, and recording with less jitter can be realized. In the above description, the example in which the optimum movement amount information of the first pulse and the last pulse is described on the disk has been described. However, the movement amount is determined only by writing the movement information of only one of the pulses on the disk. This is very useful when recording with less jitter.

In the present embodiment, the optimal position information for moving the first pulse and the last pulse in accordance with the combination of the mark and the space is recorded on the disc. However, the description has been given in the first embodiment. As described above, a recording method in which the pulse widths of the first pulse and the last pulse are changed may be used. Since the optimum width information is recorded on the disk, optimum recording can be performed even if the type of the optical disk such as the disk structure or the recording film is different.

In addition to changing the position and width of the pulse,
There are a plurality of methods for controlling the mark start position and the mark end position, such as changing the light emission power of a specific pulse. Therefore, it is important to record the control method together with the TF and TL tables together with the table in order to perform accurate recording.

FIG. 25 is a plan view of the optical disk 2501. In FIG. 25, reference numeral 2502 denotes a data area which is used by a user to record information. Reference numeral 2503 denotes an area in which information for determining an adjustment method of a first pulse and a last pulse according to an input signal is recorded.
The innermost circumference of the disk is formed by a row of pits having irregularities.
Reference numeral 2504 denotes position information of the optimum or representative mark start and end portions at the time of manufacturing the disc, that is, FIG.
(A) or an area in which the table of FIG. 24 is recorded, which is composed of an uneven pit row on the innermost circumference of the disk.

By reproducing the area 2503, it is possible to know whether the adjustment method is, for example, a method of moving the first pulse or the last pulse, or a method of changing the pulse width. If there is a variation in the recording device such as a difference in the shape of the light spot irradiated on the disc, the optimum positions of the mark start end portion and the mark end portion that are optimal for recording are different, so that the recording is performed in a specific area. The optimum or representative position information at the time of manufacturing the disc may be reproduced, and test recording may be performed using that state as an initial value.

As a result, it is possible to reduce the number of times a pattern is repeatedly recorded until the optimum position for recording data is determined, thereby shortening the time required for optimization.

FIG. 26 is a plan view of the optical disk 2601. In FIG. 26, reference numeral 2602 denotes a data area, which is used by a user to record information. Reference numeral 2603 denotes an area in which information for determining an adjustment method of the first pulse and the last pulse according to the input signal is recorded.
The innermost circumference of the disk is formed by a row of pits having irregularities.
Reference numeral 2604 denotes an area in which the position information of the optimum or representative mark start and end portions at the time of manufacturing the disc is recorded. The innermost circumference of the disk is formed by a row of pits having irregularities. Reference numeral 2605 denotes a test recording area. Region 26
03 and 2604, by performing test recording in the area 2605, for example, as described in the first embodiment, more optimal recording than in the case of recording data with only one set value. Can be realized.

As shown in FIG. 25, an area 2503 in which information for determining a method of adjusting a first pulse and a last pulse in accordance with an input signal is recorded in an optimal or representative manner in manufacturing a disc. By arranging the mark information inside the area 2504 where the position information of the start and end portions of the mark is recorded, when reproducing from the inner circumference side, the recording method can be promptly recognized, and depends on the recording method. It is possible to save time until ending the setting to be performed.

Similarly, as shown in FIG. 26, an area 2603 in which information for determining a method of adjusting a first pulse and a last pulse in accordance with an input signal is recorded in an area 2603 that is optimal or representative during disc manufacturing. Area 2604 in which positional information of a typical mark start and end is recorded
By arranging it on the inner side, when reproducing from the inner peripheral side, it is possible to quickly recognize the recording method, and it is possible to save time until ending the setting depending on the recording method.

Although the embodiment has been described using an optical disk, the present invention is not limited to this. It is obvious that the same effect can be obtained in a tape-shaped or card-shaped recording medium and its recording / reproducing apparatus. , Within the scope of the present invention.

[0177]

According to the configuration of the optical information recording apparatus of the present embodiment, by recording the first to fifth patterns, the optimum movement amount of the first pulse and the last pulse according to the data pattern can be obtained. Is obtained, and the obtained first pulse and / or last pulse movement amount information are recorded on a recording medium at the production stage, and when the user records data, the recorded movement amount information is recorded. Can be omitted, learning time can be shortened for shortening the learning time and mark position accuracy can be improved, and recording with less jitter can be realized.

Further, according to the configuration of the information recording medium of the present embodiment, data for changing the mark start and end positions recorded in a specific area of the information recording medium in accordance with an input signal is reproduced. By setting the recording device, optimum recording can be performed even if the type of the optical disk such as the disk structure or the recording film is different.

[Brief description of the drawings]

FIG. 1 is a block diagram of an optical information recording apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a signal according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a recording pulse train according to the first embodiment of the present invention.

FIG. 4 is a classification diagram of pulse movement according to the first embodiment of the present invention;

FIG. 5 is an explanatory diagram of a classification method according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram of a classification method according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram of a classification method according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram of a classification method according to the first embodiment of the present invention.

FIG. 9 is an explanatory diagram of a classification method according to the first embodiment of the present invention.

FIG. 10 is a frequency characteristic diagram of a reproduction equalizer according to the first embodiment of the present invention.

FIG. 11 is an explanatory diagram of a signal according to the first embodiment of the present invention.

FIG. 12 is an explanatory diagram of a signal according to the first embodiment of the present invention.

FIG. 13 is an explanatory diagram of a signal according to the first embodiment of the present invention.

FIG. 14 is an explanatory diagram of a signal according to the first embodiment of the present invention.

FIG. 15 is a block diagram of an optical information recording device according to a second embodiment of the present invention.

FIG. 16 is a plan view of an information recording medium according to a second embodiment of the present invention.

FIG. 17 is an explanatory diagram of a signal according to the second embodiment of the present invention.

FIG. 18 is an explanatory diagram of a recording pulse train according to the second embodiment of the present invention.

FIG. 19 is a classification diagram of pulse movement according to the second embodiment of the present invention.

FIG. 20 is a waveform chart illustrating the amount of movement of the first pulse according to the present invention.

FIG. 21 is a waveform chart illustrating the movement amount of the last pulse according to the present invention.

FIG. 22 is a waveform chart illustrating adjustment of the width of a first pulse according to the present invention.

FIG. 23 is a waveform chart illustrating adjustment of the width of the last pulse according to the present invention.

FIG. 24 is a modified example of a classification diagram of pulse movement according to the present invention.

FIG. 25 is a plan view of an optical disk according to the present invention.

FIG. 26 is a plan view of an optical disc according to the present invention.

FIG. 27 is a block diagram of an optical disc master cutting apparatus according to the present invention.

FIG. 28 is an explanatory diagram of a signal according to the first embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 101 optical disk 102 spindle motor 103 semiconductor laser 109 laser driving circuit 110 pulse moving circuit 111 pulse generating circuit 120 pulse displacement measurement circuit 201 first pattern signal 1101 second pattern signal 1201 third pattern signal 1301 fourth pattern signal 1401 fifth pattern signal 1501 optical disk 1520 memory

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-287465 (JP, A) JP-A-5-290437 (JP, A) JP-A-5-135363 (JP, A) JP-A-2- 5221 (JP, A) JP-A-63-121130 (JP, A) JP-A-5-62191 (JP, A) JP-A-9-81937 (JP, A) JP-A-5-234079 (JP, A) WO 97/14143 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B ^7/ 00-7/013 G11B 7/125

Claims (10)

(57) [Claims] 1. A method according to claim 1, wherein only a first pulse, only a first pulse and a last pulse, a plurality of tracks formed concentrically or spirally, and a mark portion of an original signal recorded on the track are provided. The first pulse, the last pulse, and a combination of the number of one or a plurality of multi-pulses existing between the first pulse and the last pulse are irradiated with a light beam onto the recording surface of the track using a drive pulse whose number of pulses is adjusted. An information recording medium for recording information in a space between a mark and a mark, comprising: a data recording section for recording data; and a specific information recording section. By changing the first pulse moving amount TF of the drive pulse determined by the combination with the length of the space portion of The formation of the start end of the mark is adjusted by adjusting the amount of the first pulse movement amount TF such that the reproduction jitter becomes equal to or less than a certain value. The space portion immediately before the mark portion is classified into three or more length types, one including only two pulses, and the other including a first pulse, a last pulse, and a multipulse included therebetween. Are also classified into three or more types of lengths, and a total of nine or more first-pulse movement amounts T for adjusting the start of a mark.
There are at least two methods of using the value of F and the first pulse movement amount for the first pulse of the plurality of drive pulses, a method of moving the first pulse and a method of changing the width of the first pulse. The code indicating the above method is recorded in advance, and the position where the code indicating the above method is recorded is at a position preceding the position where the value of the first pulse movement amount is recorded in the information recording direction. An information recording medium characterized by being recorded. 2. The moving amount TF of the first pulse is represented by a time difference TF between a first reference point R1 which is a leading edge of a mark portion of an original signal to be recorded and a starting edge of a first pulse of the plurality of driving pulses. 2. The information recording medium according to claim 1, wherein the information is recorded. 3. The length of each of the mark portion of the original signal and the space portion between the mark portions is NT (where N is a positive integer from n1 to n2), where T is the reference period. ), And the mark and space parts are
2. The information recording medium according to claim 1, wherein each of the first and second moving distances TF is divided into a plurality of categories according to the length of the mark and the space, and a specific value is set for each category. 4. The information recording medium according to claim 1, wherein the mark portion is classified into four length types, and the space portion is also classified into four length types. 5. The information recording medium according to claim 1, wherein each of the mark portion and the space portion is finely classified as the mark portion and the space portion become shorter. 6. The information recording medium according to claim 3, wherein n1 is 3, and n2 is 11. 7. A mark portion is classified into three types of 3T, 4T and 5T or more, and a space portion is classified into 3T, 4T and 4T.
4. The information recording medium according to claim 3, wherein the information recording medium is classified into three types, T and 5T or more. 8. The mark portion is 3T, 4T, 5T, 6
Classified into four types of T or more.
4. The information recording medium according to claim 3, wherein the information recording medium is classified into four types of T, 4T, 5T, and 6T or more. 9. A plurality of tracks formed concentrically or spirally and only a first pulse, only two pulses of a first pulse and a last pulse, a first pulse and a last pulse according to the length of a mark portion of an original signal. And a mark formed by irradiating the recording surface of the track with a light beam using a drive pulse whose number of pulses is adjusted by a combination of the number of one or more multi-pulses existing between the mark and the mark, A data recording unit for recording information in a space between the marks, and a specific information recording unit, wherein the specific information recording unit has a mark length and a space length immediately before the mark portion. The formation of the start end of the mark is adjusted by changing the first pulse movement amount TF of the drive pulse determined by the combination. The value of the first pulse movement amount TF such that the reproduction jitter is equal to or less than a certain value, and the mark portion includes a first pulse only, a first pulse and a last pulse including only two pulses, The first pulse, the last pulse, and the multi-pulse included between them are classified into three or more length types, and the space portion immediately before the mark portion is also classified into three or more length types. And a first pulse movement amount T for adjusting the start of the mark at a total of nine or more.
There are at least two methods of using the value of F and the first pulse movement amount for the first pulse of the plurality of drive pulses, a method of moving the first pulse and a method of changing the width of the first pulse. The code indicating the above method is recorded in advance, and the position where the code indicating the above method is recorded is at a position preceding the position where the value of the first pulse movement amount is recorded in the information recording direction. An apparatus for recording / reproducing a recorded information recording medium, comprising: means (15) for reproducing a first pulse moving amount TF and a code indicating a method prerecorded on the information recording medium.
05-1508, 1512-1517), a means (1520) for storing a reproduced first pulse movement amount TF and a code indicating the method, a drive pulse is generated by a recording data signal, and the generated drive pulse is generated. , The first pulse movement amount TF
(1510) means for correcting with a method and a code indicating the method
Means (1) for generating a light beam by the corrected drive pulse to form a space and a mark on the information recording medium.
09, 103-106). 10. The reproducing means includes an equalizer (15).
14), and the ratio of the output amplitude of the equalizer to the frequency of the longest mark included in the same classification and the output amplitude of the equalizer to the frequency of the shortest mark is 3d.
10. The apparatus according to claim 9, wherein B is equal to or less than B.